As you’ve just stated, finasteride is not effective if a person has lost some hair due to radiation. But would a transplant be effective in that case?
The type of radiation that you got and the extent of skin damage will dictate how well the scalp will do with a hair transplant. If you or your doctor have doubts about survival of a hair transplant, we often do a test hair transplant of 20-50 grafts taken out FUE style and then wait 6-8 months and see the yield. If the yield is good, then a full transplant will do just fine. Finasteride may or may not have value in the radiated area if the radiation killed off the hair.